Biological filtration is a method that uses naturally occurring nitrifying bacteria to detoxify nitrogenous wastes. One type of bacteria (Nitrosomonas spp.) converts ammonia to nitrite while another naturally occurring bacteria (Nitrobacter spp.) converts the nitrite into a far less harmful form of nitrogen waste: nitrate.

Nitrite is a strongly toxic intermediate stage for fish and invertebrates. As its level increases, the function of hemoglobin necessary for the transport of oxygen in fishes' blood gets blocked. Lethal concentrations cause chronic stress lowering fish's resistance to parasite and bacterial attacks, reducing food intake and growth, and can result in death. Apart from that, it causes damage to fishes' natural barriers and can stimulate cancer in the digestive system.

Nitrite levels in excess of 0.1 mg/L are considered dangerous to many ornamental fish as well as invertebrates for which, levels higher than 0.05 mg/L are already unacceptable. If bacterial oxidation process is impeded; for example by new filter material, this can lead to harmful rise in the nitrite ion concentration. For this reason, regular use of a nitrite test kit is an absolute requirement.

The NO2 Test kit from ELOS, especially developed for freshwater and seawater aquariums, allows the determination of the Nitrite level with the help of a finely tuned color scale, which shows a range of 0-2 mg/L.

General Information
In order to maintain good water quality, a range of test kits that offer accuracy, consistency and support is an integral part of a successful aquarium. ELOS AquaTest Kits are designed, manufactured and tested to standards that are unparalleled in this industry. All ELOS AquaTest kits provide the following:

Calibrated Droppers: Bottles are designed to provide a consistent drop size, which is a key element in testing - regardless of who is squeezing the bottle the drop remains consistent. Many less expensive brands will rely on the cheapest possible bottles, syringes and tips that can easily skew the test results.

While all chemicals should be considered dangerous and handled accordingly, ELOS uses the highest-quality reagents that are nontoxic. All ELOS boxes, instructions and reagents are clearly labeled along with childproof packaging - that amazingly is not found in some of our competitors who base their kits largely on toxic chemicals! Of course, it is more costly to use such a high grade of reagents, use proper packaging and labels, but ELOS feels it is necessary. In some kits, you will even notice a raised label for people who are vision impaired.

Validation of Each Reagent Batch: NIST (National Institute of Standard and Technology) certified samples. While some may claim to use, "lab quality components" in their kits, ELOS validates each batch of reagents using these NIST certified samples.

Careful Batch Management: All chemical test kits are susceptible to damage from extreme temperatures. ELOS carefully ships and stores our test kits before they ship to the retailer or final customer. This is a vital step that often is neglected.

Written and Illustrated Instructions: Along with professionally calibrated color charts (when needed) make it easy for beginners through to experts, to use the kit correctly. Expiration dates, batch and lot numbers in every kit and every reagent, allow ELOS to carefully track - and when needed - assist customers with questions about their kit.

When purchasing your next kit, compare our track record of reliability, consistency and support, with any other test kit range on the market, and you will see that no test kit company compares. The ELOS Aqua Test Kit range is truly, a lab quality kit designed for the hobbyist.

Don't take the quality of your tap water for granted. If you draw your water from a well, nature may not be providing you the perfect balance. If you are using tap water from your municipal department, it likely includes minerals and additives.

Serious hobbyists know that the best way to measure the salinity and specific gravity of aquarium water is to use a refractometer. These precision optical instruments are incredibly accurate even at very low salt levels, and are equally easy to use.

Testing your water parameters is an important method of foreseeing problems in your aquatic ecosystem before they result in catastrophe. Luckily, tools that were once only accessible (and affordable) to advanced hobbyists have since become simpler.